Question

我无法理解为什么这段代码会因segfault而失败：

#include <cstdlib>
#include <iostream>
#include <map>
#include <string>

using namespace std;

int main(int argc, char** argv) {

    map <string, string> temp;
    map <string, string>::iterator it;

取值
string text =“”; string thatChange =“”; string whatChange =“”;

    getline (cin, text);


    while (true)
    {
        getline (cin, thatChange);
        if (thatChange == "-1")
            break;

        getline (cin, whatChange);
        temp.insert(pair <string, string> (thatChange, whatChange));
    }

    for (int i = 0; i < temp.size(); i++)
    {
        string thatChange = it->first ; // thatChange
        string whatChange = it->second; // whatChange
        it++;

        int index = text.find(thatChange);
        text.erase(index, thatChange.size());
        text.insert(index, whatChange);
    }

    cout << "text\n"<< text;

    return 0;
}

UPD：调试器说：

No source available for "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string() at 0x7ffff7b75928"

Answer 1

string thatChange = it->first ;

这条线唤起IN。到目前为止，it从未初始化。你应该按如下方式初始化：

it = tmp.begin();

并迭代使用地图的所有元素：

for (map<string, string>::const_iterator f = temp.begin(), e = temp.end;
     f != e;
     ++f) {
   // ....
}

Answer 2

FWIW代码片段可以编译并运行VS2010，所以如果你遇到错误，问题可能就在其他地方。

Segfault在地图中

2 个答案: